The following JAR file is missing in Dotty release 0.18.1-RC1:
lib/dotty-staging_0.18-0.18.1-RC1.jar
but is available from the Maven Central Repository:
https://search.maven.org/artifact/ch.epfl.lamp/dotty-staging_0.18/0.18.1-RC1/jar
Indeed, one can read the following in shell script bin/common:
110: DOTTY_STAGING=$(find_lib "*dotty-staging*")
and a variable $PSEP is missing on line 105 in shell script bin/dotr (before variable $DOTTY_STAGING):
105: cp_arg+="$PSEP$DOTTY_COMP$PSEP$DOTTY_INTF$PSEP$SCALA_ASM$DOTTY_STAGING"
^^^^^^